@TheSpoiler
Not sure. The Theme song is Re:Birth. IIRC, Terada mentioned something like that, too. Of course, we all remember ACE3: The Final, which was really “ACE3: This is the last time we’ll use numbers, I promise!”, and SRWs, in which the letter is only a reference to the name of the player forces, and is only important to the story half the time, so any plot significance cannot be determined.